Regional & National information- Why Recycle and Reuse Water?

The water on Earth today is the same water our ancient ancestors and even the dinosaurs used to drink, bath in, cook with and be physically made up of.  The amount of water on Earth has not changed in billions of years its only varies in where it is located (e.g. glaciers, the ocean, lakes etc…) depending on the temperature at the time.  As we make our way into the 21st century and the world’s population now stands at approximately 6.7 billion (and counting see for an up to the second figure) we are facing a major water crisis.

Humans, and indeed most living organisms, require water to live and this enormous increase in population has put a huge strain on the world’s water resources.  This is further impacted upon by the fact that towns and cities continue to grow and therefore more stormwater and effluent is produced.

Australia is a large, expansive country, with only a relatively small population (21 million) to tend to the limited water resources.  Only approximately 12% of the rainfall in Australia becomes run-off most soaks into the ground and most of that 12% is in the tropical north of Australia which is lightly developed.  In 2002 a National Land and Water Resources Audit was done which showed that 26% of surface management areas and 31% of the groundwater resources were at capacity or over-loaded.  This is a significant figure.  There is the opportunity through water recycling and reuse to at least stabilise this figure (or possible lower it) even with a rise in population and urban growth.

Many of these problems could be dealt with by harvesting, storing and cleaning up wastewater, and cheaply and efficiently storing excess rain and floodwaters to use up during dry periods.  This would provide additional access to clean water for people in cities and regional areas, and provide huge benefits for agriculture, industry, the environment and the economy.  It is also a much more sustainable way of living and preserving our planet.

Figure 1:  Mingara Sports Field Being Watered Using Recycled Stormwater  (Source: Wyong Shire Council)

Water that is suitable for recycling and reuse may come from four main sources:

  • Stormwater
  • Treated sewage effluent
  • Treated industrial discharges
  • 'Grey' water – household laundry and bathroom water

All of these water sources require additional infrastructure in order to become viable options for recycling and reuse.  The cost of which can often be justified by the huge long term benefits provided.

Figure 2:  Groundwater being extracted on the Central Coast  (Source: Wyong Shire Council)  

Australia has been criticised for being the second highest user of domestic water resources in the world (behind the USA) according to CSIRO scientists but, we also have the technology and the expertise to become world leaders in water recycling and reuse.  In Australia (as a whole) approximately 97% of our city runoff and 86% of effluent water is unproductive and unused.  Wastewater, which may be rich in pollutants and nutrients, flows from our cities and farms into rivers and coastal areas.  This water has the potential to harm industry and the environment, inhibit future development and add to pollution in our rivers and estuaries.  In Australia we are currently quite limited in the ways in which wastewater can be used.  This is because wastewater may pose a health and environmental risk if used in an uncontrolled way.  

The CSIRO suggest that recycled water could provide a major resource for a range of services, many of which are already being used on the Central Coast.  A further use which has been suggested is to put water back into aquifers, to recharge the groundwater.  This process is called aquifer storage and recovery (ASR).  This process was originally used for stormwater only but now treated effluent is also being used successfully.  Research is still continuing into this method and other options are being investigated.

Often water that has come from cities, agriculture or industry contains contaminants which make it unsuitable for recycling.  Sewage effluent and water from industry must be treated before it can be put into aquifers.  Stormwater usually requires less treatment and the use of a wetland style system may be sufficient.  One of the great benefits of ASR is that when the water is inserted under the ground it is not exposed to oxygen and natural micro-organisms may kill disease-causing organisms in the water.  Depending on the time the water spends underground (the longer the better) the water that is extracted may even be suitable for drinking.

Figure 3:  Mangrove Dam in drought (Source: Wyong Shire Council)

The recent years of drought which have affected most of Australia have resulted in water restrictions being imposed (see Gosford/Wyong Councils’ Water Authority site for latest restrictions and the requirements). These restrictions have caused the State and Local governments to re-evaluate the way in which water is used and look for alternate water resources.  For example in both Gosford City and Wyong Shire Council areas it is compulsory for water tanks to be installed in new developments.  There are rebates (money back) from Council which applies whenever a tank is installed.

There are now over 500 sewage treatment plants (STPs) across Australia, including most plants on the Central Coast, that now recycle at least part of their treated effluent.  

In Australia there is now a push to adopt the term ‘drinking water’ instead of ‘potable water’ and use ‘water recycling’ as the term used to describe water reclamation, recycling and reuse.  It is thought that this would help with the acceptance of such water schemes in urban areas.  It has been suggested that a national approach to the costs and pricing of drinking water and recycled water is necessary to ensure the public feels ‘safe’ with the new system.

There is also scope for the increased use of wetlands, especially artificial/man-made ones, to ‘clean’ reclaimed water.  Many recent projects throughout Australia have not utilised this option which is considered to be both cost effective and environmentally friendly.  It is also essential that the public remain well informed and aware of all of the recycling and reuse options that are now available due to an increase in technology.